Download TMJ - IS MU

ARTICULATIO
TEMPOROMANDIBULARIS
Temporomandibular joint
 Allows for movement of the mandible for
speech and mastication
 Most frequently used articulation
 Their correct functioning, several other
vegetative and relational functions more or less
are based on their performance
 Adaptable
1. ARTICULAR SURFACES
2. JOINT CAPSULE
3. DISCS OF THE JOINT
4. LIGAMENTS
5. JAW MOVEMENTS
6. INERVATION
7. ARTERIAL SUPPLY
8. EXAMINATION OF THE JOINT
9. TOPOGRAPHY RELATIONSHIP
1. ARTICULAR SURFACES
 The articular fossa
 The articulatar eminence
 The postglenoid process
 The head of the condyle
Angle 130°- 180°
http://www.dr-wolter-kfo.de/pdf/mandibular_1999.pdf
2. JOINT CAPSULE
 A thin fibrous
 Cone-shaped
 The medial and lateral
walls are reinforced by
the medial and lateral
ligaments
 The superior capsular attachments are
relatively loose → translate forward on
mandibular depression
 The inferior attachments are more tightly bound
to the capsule → translate forward with the
condyle during mandibular depression
 The inner surface are covered by synovial
membrane → synovial fluid → nutrients to
avascular cartilage and to reduce a friction
3. DISC OF THE JOINT
 An oval, firm, fibrous plate that lies between the
head of the mandibule, mandibular fossa and
articular tubercle
 Reduce sliding friction and to dampen load
spikes and allow the mouth open and close
Articular surface are separated by disc to:
1. upper compartment
between the disc and mand. fossa (1,2ml)
2. lower compartment
between the condyle and the disc (0,9ml)
 Disc is biconcave with fibrocartilaginous
structure
 Matrix of disc consists primally of colagen and
elastic fibres
 In the pars anterior and posterior run
transverse collagens fibres
 Based upon the function is divided into anterior,
intermedia and posterior partes
 Posterior part of the articular disk, so-called
bilaminar, separates into upper and lower
laminae of collagen fibres both insert into the
posterior wall
 Between these laminae and the posterior wall
is filled with retroarticular Zenker plastic pad
Retroarticular Zenker plastic pad
 The posterior part becomes gradually losser
and is continuous with the loose connective
tissue and the fat lobules filling the retroarticular
space
 The connective tissue contains a venous
plexus, numerous nerve fibres and fat
(pterygoid plexus and auriculotemporal nerve)
The pad is responsible for stabilizing the disc on
the condyle and supplying the joint
On opening
a Zenker plastic pad of retrodiscal tissue filled
the space between the posterior thick part of the
disc and the condyle as a result of negative
pressure
On closing
the blood is pushed out the retromandibular vein
Attachment of articular disc
Frontal
section
Disc
Medially and laterally is the disc attached to the
inner periphery of the articular capsule → tightly
bound to the capsule, causing the disc to translate
forward with the condyle during depression
Innervation of articular disc
 The nonmyelinated
and the myelinated nerve
 Free nerve endings
 Sensory nerve end
organs
Physiologic disc position
 Pars posterior of the disc lies on the superior
portion of the condyle
 In the centric condylar position the pars
intermedia is located between anterosuperior
convexity of the condyle and the articular
protuberance
 Pars anterior lies in front of condyle
Dislocation of the articular disc
 Displacements of the disc in the anterior
anteromedial, or anterolateral direction
 Posterior disc displacement - on rare occasions
 With or without reduction
 The combination of ant. and lat. or medial
displacement is called rotational displacement
 Pure lateral or pure medial displacement is
called sideways displacement
 Chronic displacement is
resulting in deformity of the
disc
 In approximately 10% of
patients presenting with
pain and dysfunction
Trauma of the articular disc
Microtrauma
bruxism, stress, malocclusion, bad habits,
chewing gum
Macrotrauma
an injury - either directly to the joint or to the head
and neck intubation, lengthy dental work
4. LIGAMENTS OF THE TMJ
Ligaments have three main functions:
a) stabilization
b) guidance of movement and
c) limitation of movement
 Articular: lateral
medial
 Extraarticular stylomandibular
sphenomandibular
 Discomalleolar (Pinto´s) + Tanaka´s ligament
Lateral ligament
From processus zygomaticus
and articular tubercle
→ mandibular neck
 A superficial, more vertically
oriented part limits jaw
opening
 A deep, more horizontal part
limits retrusion and
laterotrusion
Medial surface of
articular capsula
with medial lig.
Stylomandibular ligament
From styloid process →
the posterior edge of the
angle of the mandible
 Restricts protrusive and
mediotrusive movements
+ prevent excessive
upward rotation
Sphenomandibular ligament
From sphenoidal spine
→ lingula of the mandible
 Limits protrusive and
mediotrusive movement
+ passive jaw opening
Diskomaleolar (Pinto´s) ligament
 Connection between the malleus and the
medial wall of the articular capsule and disc
 Passes through the squamotympanic fissure
to the middle ear
 Caused the tinnitus and secondary
inflammation of temporomandibular joint
5. MOVEMENTS OF THE TMJ
Hinge movement - type of rotation takes place
in the lower compartment between the stationary
disc and the moving condyle
Gliding movement - takes place in the upper
compartment between the superior surface of the
disc, which is moving, and mandib. fossa
Depression - the opening
Lateral pterygoid + supra- and infrahyoid m.
 With simple rotation at the joint can be achieved
15 - 20mm intericisor distance
 During translation, the disc and condyle move
under the articular eminence
Elevation - the closing
Temporal + masseter + medial pterygoid m.
 Translation - the condyles move backward and
upward along the articular eminence
 Rotation upward to attain centric position
Protrusion
Lateral et medial pterygoid + masseter m.
 Slide the mandible forward
 Maximal protrusion results in the lower incisors
being a few mm anterior to the maxillary incisors
Retrusion
Temporal + masseter m.
 Move the mandible posteriorly
 Condyles move backward and upward and
reoccupy the mandibular fossa
Laterotrusion
Lateral et medial pterygoid + masseter +
temporal m.
The condyle move to the right or to the left side
During lateral movements,
the each of condyle moves differently:
on the working side - rotates around a
vertical axis and moves lat. and ant.
on the nonworking side - ant., inf. and med.
Hyper mobility
Subluxation
Self-reducing, incomplete dislocation of a joint in
which the patient is able to close his or her mouth
without assistance
Luxation (true dislocation)
Joint is displaced from its articulations and
requires manipulation by another individual to
return to its normal position
Hypo mobility
Ankylosis (intracapsular)
The fibrous adhesions or bony fusion between
condyle, disc, glenoid fossa, and eminence
Pseudoankylosis (extracapsular)
Pathology extrinsic to the joint
6. INERVATION OF THE TMJ
7. ARTERIAL SUPPLY OF THE TMJ
8. EXAMINATION OF TMJ
Palpation of the preaurikular area
Posterolateral and posterosuperior compression
Imaging procedures
Specific radiography
Conventional
Ortopantomography
CT
MRI
Arthroscopy
Normally performed under general anaesthesia
Arthroscopy upper compartment or lower
compartment
CAVE! injury to the auriculotemp. and facial nerve
9. TOPOGRAPHY RELATIONSHIP
Cranially
medial cranial fossa
Dorsally
external auditory
Laterally
glandula parotis
superficial temp. a.,v.
auriculotemporal n.
Medially
chorda tympani